Spore-associated bacteria of arbuscular mycorrhizal fungi

Maritime sand dunes represent a harsh environment where plants face several different stresses, from drought and salinity to seasonal extreme temperatures, high evaporation rates, dune instability and low levels of nutrients and organic matter. It has long been known that Ammophila arenaria can thrive in nutrient-poor and challenging environments like maritime sand dunes thanks to the support of arbuscular mycorrhizal fungi (AMF), a group of beneficial soil microorganisms. AMF are facilitated and complemented by bacterial populations living associated with their hyphae and spores and playing important roles as plant growth promoting (PGPB) and mycorrhiza helper (MHB) bacteria. In this study we assessed the diversity of AMF spore wall-associated bacteria and spore endosymbionts in A. arenaria rhizosphere. The bacterial microbiota of the two most abundant AMF species (Racocetra persica and Racocetra fulgida) was characterised using Illumina high-throughput metagenomic sequencing.